For the manufacturer's indications of the Duonix PS100 device on its download website, I updated the device in a free way to the Update_08.08.2017 version, for a correct and better operation in devices of the HW4 type like mine.
After having updated the device to the version indicated by the manufacturer, the message INTERNAL FAILURE appears permanently in German!
Contact with the Technical Department of Duonix by e-mail, briefly advising me to replace the micro SD internal card, load the update again, and then provide them with the identification number. To provide me with an activation key for this new card.
The key that Duonix gives me is rejected as invalid. After my insistence on solving the problem, I suggest to acquire another new micro SD card with lower capacity, than previously installed.